• Journal of Information Processing Systems
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• v.13 no.6
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• pp.1613-1627
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• 2017

The concept of the Internet of Things (IoT) enables physical objects or things to be virtually accessible for both consuming and providing services. Undue access from irresponsible activities becomes an interesting issue to address. Maintenance of data integrity and privacy of objects is important from the perspective of security. Privacy can be achieved through various techniques: password authentication, cryptography, and the use of mathematical models to assess the level of security of other objects. Individual methods like these are less effective in increasing the security aspect. Comprehensive security schemes such as the use of frameworks are considered better, regardless of the framework model used, whether centralized, semi-centralized, or distributed ones. In this paper, we propose a new semi-centralized security framework that aims to improve privacy in IoT using the parameters of trust and reputation. A new algorithm to elect a reputation coordinator, i.e., ConTrust Manager is proposed in this framework. This framework allows each object to determine other objects that are considered trusted before the communication process is implemented. Evaluation of the proposed framework was done through simulation, which shows that the framework can be used as an alternative solution for improving security in the IoT.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.554-557
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• 2016

Recently, supercomputer has been increasingly adopted as a computing environment for scientific simulation as well as education, healthcare and national defence. Especially, supercomputing system with heterogeneous computing resources is gaining resurgence of interest as a next-generation problem solving environment, allowing theoretical and/or experimental research in various fields to be free of time and spatial limits. However, traditional supercomputing services have only been handled through a simple form of command-line based console, which leads to the critical limit of accessibility and usability of heterogeneous computing resources. To address this problem, in this paper, we provide the design and implementation of web-based HPC (High Performance Computing) job management framework for computational scientific simulation. The proposed framework has highly extensible design principles, providing the abstraction interfaces of job scheduler (as well as bundle scheduler plug-ins for LoadLeveler, Sun Grid Engine, OpenPBS scheduler) in order to easily incorporate the broad spectrum of heterogeneous computing resources such as cluster, computing cloud and grid. We also present the detailed specification of HTTP standard based RESTful endpoints, which manage simulation job's life-cycles such as job creation, submission, control and status monitoring, etc., enabling various 3rd-party applications to be newly created on top of the proposed framework.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.68-69
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• 2015

Traditional External Insulation Finishing System(EIFS) is applied to apartment construction by performing structural framework and insulation finishing work sequentially. Separate execution of the three works increases construction cost and duration. Concurrent construction method of EIFS, which performs framework and insulation finishing work simultaneously, is introduced in order to solve these problems. However, the introduced method is exposed to the risk of construction delay caused by bottlenecks due to interacting processes and resources. Therefore, this paper presents a simulation model suitable for estimating work productivity of the concurrent construction by considering predecessor and successor processes to optimize resource allocation and minimize construction delay.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.155-161
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• 2001

Federated process framework is introduced responding to market\\`s needs to gain benefits of process information sharing in a virtual enterprise. The framework is verified by implementing its prototype system. However, it is very difficult to integrate developed prototype system with operating legacy systems to show its applicability. Thus, a test bed approach is widely adopted to provide a system environment that imitates the operations of real legacy systems and their interactions. In this paper, we described implementation detail of test bed imitating the real-world workflow systems. We also show its contribution and results of the prototype system that was implemented on the test bed.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.2
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• pp.109-115
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• 2014

Analyzing large scale data has become an important activity for many organizations. Since MapReduce is a promising tool for processing the massive data sets, there are increasing studies to evaluate the performance of various algorithms related to MapReduce. In this paper, we first develop a simulation framework that includes MapReduce workload model, data center model, and the model of data access pattern. Then we propose two algorithms that can reduce the energy consumption of MapReduce systems. Using the simulation framework, we evaluate the performance of the proposed algorithms under different application characteristics and configurations of data centers.

• Nuclear Engineering and Technology
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• v.48 no.2
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• pp.470-481
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• 2016

Field-programmable gate arrays (FPGAs) have received much attention from the nuclear industry as an alternative platform to programmable logic controllers for digital instrumentation and control. The software aspect of FPGA development consists of several steps of synthesis and refinement, and also requires verification activities, such as simulations that are performed individually at each step. This study proposed an integrated software-testing framework for simulating all artifacts of the FPGA software development simultaneously and evaluating whether all artifacts work correctly using common oracle programs. This method also generates a massive number of meaningful simulation scenarios that reflect reactor shutdown logics. The experiment, which was performed on two FPGA software implementations, showed that it can dramatically save both time and costs.

• Journal of the Korean Society for Railway
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• v.9 no.5 s.36
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• pp.511-516
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• 2006

A standard framework of CFD(Computational Fluid dynamics) analysis for railway system has been developed to evaluate the overall aerodynamic performance of railway system and has been adopted to numerical simulation of the pressure field around KTX train. The framework is composed of standard aerodynamic model and standard aerodynamic performance to customize the general CFD solution process reflecting the characteristics of railway system such as various operation mode and performance factors. The results show that the standard framework of CFD analysis for railway system can provide objectivity and consistency to the CFD analysis for railway system and the pressure field around KTX train has been successively solved.

• KIEE International Transactions on Power Engineering
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• v.4A no.2
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• pp.73-78
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• 2004

This paper proposes a framework for determining the minimum load shedding for restoring solvability. The framework includes a continuation power flow (CPF) and an optimal power flow (OPF). The CPF parameterizes a specified outage from a set of multiple contingencies causing unsolvable cases, and it traces the path of solutions with respect to the parameter variation. At the nose point of the path, sensitivity analysis is performed in order to achieve the most effective control location for load shedding. Using the control location information, the OPF for locating the minimum load shedding is executed in order to restore power flow solvability. It is highlighted that the framework systematically determines control locations and the proper amount of load shedding. In a numerical simulation, an illustrative example of the proposed framework is shown by applying it to the New England 39 bus system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.12
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• pp.1228-1236
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• 2013

In this paper, we present a development framework for acquiring intelligent but complex cyber-physical weapon systems based on modeling and simulation development tools for cyber-physical systems, EcoSUITE. We introduce EcoPOD that models weapon systems and EcoSIM that provides constructive simulation environment for interoperating the weapon model to be developed with other weapon models. To develop cyber-physical weapon system based on LVC interoperation, an interoperation architecture and an interface technique for a live and a virtual system that is compliant with the interoperation architecture. By expanding EcoSuite, we provide LVC-based development framework for interoperating a real system, a human-interactive interface system, and simulation models and validate it with a case study.

• Journal of the Korea Society for Simulation
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• v.20 no.4
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• pp.97-104
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• 2011

Defense M&S software industry has carried out a variety of studies related to an efficient implementation of large-scale simulation and interoperability with respect to each of the system and HLA has been developed to provide a common architecture for distributed simulation of them. HLA defines Federate interface specification and provides services through RTI. Meanwhile, the difficulty lies in developing the software based HLA. Federate developer needs to understand how to handle Metadata produced RTI and has to modify the interface code whenever FDD is modified. This paper presents the implementation method of SOM interface using the code generation technique and middleware architecture for providing simple API. It solves the problem for implementing the framework of distributed object communication by using proposed method.